Mercedes-Benz E420 front fog lights use H1 and H3 bulb sizes, while rear fog lights require P21W bulbs. The replacement chart covers 1994 to 1997 production years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Mercedes-Benz E420 front fog light uses two different bulb types across its model years: the H3 for 1994-1995 and the H1 for 1997.
The H3 is an ECE-standard single-filament halogen bulb rated at 12V and 55W, fitted with a PK22s base. It holds approval in the US and Japan in addition to Europe and worldwide markets.
The H1 is also an ECE-standard single-filament halogen bulb rated at 12V and 55W, but it uses a P14.5s base rather than the PK22s found on the H3. Despite sharing the same voltage and wattage, the two bulbs are not interchangeable due to their differing base types.
The rear fog light on the E420 uses the P21W bulb for both 1995 and 1997.
The P21W is a single-filament signalling bulb rated at 12V and 21W, fitted with a BA15s bayonet base. Its lower wattage reflects its role as a signalling lamp rather than an illumination source.
The BA15s bayonet base on the P21W is a single-contact design, which is consistent with its single-filament construction and distinguishes it from dual-contact bayonet bulbs used in other signalling applications.
All three bulb types listed in the E420 specifications conform to ECE standards, indicating compatibility with European and worldwide regulatory requirements as well as US and Japanese approvals.